You've seen how a repository can be accessed in many different ways. But is it possible—or safe—for your repository to be accessed by multiple methods simultaneously? The answer is yes, provided you use a bit of foresight.
At any given time, these processes may require read and write access to your repository:
regular system users using a Subversion client (as
themselves) to access the repository directly via
file:///
URLs;
regular system users connecting to SSH-spawned private svnserve processes (running as themselves) which access the repository;
an svnserve process—either a daemon or one launched by inetd—running as a particular fixed user;
an Apache httpd process, running as a particular fixed user.
The most common problem administrators run into is repository
ownership and permissions. Does every process (or user) in the
previous list have the rights to read and write the Berkeley DB
files? Assuming you have a Unix-like operating system, a
straightforward approach might be to place every potential
repository user into a new svn
group, and
make the repository wholly owned by that group. But even that's
not enough, because a process may write to the database files
using an unfriendly umask—one that prevents access by
other users.
So the next step beyond setting up a common group for
repository users is to force every repository-accessing process
to use a sane umask. For users accessing the repository
directly, you can make the svn program into a
wrapper script that first sets umask 002 and
then runs the real svn client program. You
can write a similar wrapper script for the
svnserve program, and add a umask
002 command to Apache's own startup script,
apachectl
. For example:
$ cat /usr/bin/svn #!/bin/sh umask 002 /usr/bin/svn-real "$@"
Another common problem is often encountered on Unix-like
systems. As a repository is used, Berkeley DB occasionally
creates new log files to journal its actions. Even if the
repository is wholly owned by the svn group,
these newly created files won't necessarily be owned by that
same group, which then creates more permissions problems for
your users. A good workaround is to set the group SUID bit on
the repository's db
directory. This causes
all newly-created log files to have the same group owner as the
parent directory.
Once you've jumped through these hoops, your repository should be accessible by all the necessary processes. It may seem a bit messy and complicated, but the problems of having multiple users sharing write-access to common files are classic ones that are not often elegantly solved.
Fortunately, most repository administrators will never
need to have such a complex configuration.
Users who wish to access repositories that live on the same
machine are not limited to using file://
access URLs—they can typically contact the Apache HTTP
server or svnserve using
localhost
for the server name in their
http://
or svn://
URLs.
And to maintain multiple server processes for your Subversion
repositories is likely to be more of a headache than necessary.
We recommend you choose the server that best meets your needs
and stick with it!